With a tight majority, Allen’s willingness to speak out could spell trouble for May.

PARTY: Conservative

POSITION: Backbencher MP

MP SINCE: 2015

REMAINIAC OR BREXTREMIST? Remain

Return to the full list of 40 Brexit troublemakers to discover who to watch as legislation disentangling Britain from the European Union goes through the U.K. parliament. For an explanation of how this list was compiled, see here.